That is the central idea of ​​a study carried out by a researcher at the University of Manchester that proposes a novel strategy, based on the so-called “game theory”, to increase the chances of finding extraterrestrial civilizations. The work, carried out by astrophysicist Eamonn Kerins, from the Jodrell Bank Observatory at the University of Manchester, has just been published in The Astronomical Journal. The current search programs of SETI, an Institute whose work focuses on finding civilizations “out there”, tend to have two approaches: The first is to “sweep” a large area of ​​sky in the hope of picking up, somewhere, a signal that indicates the presence of intelligent beings.

The method has the disadvantage that it generates a huge volume of data very quickly, among which it is very difficult to find what you are looking for. The second is based on a “directed search”, focusing on specific star systems where it is known that there may be planets capable of supporting life. The risk, of course, is to dedicate a lot of resources to few candidates, in which it could, as it happens, not be made. A new idea to search and this is where Kerins’ idea fits in. An idea that, according to the researcher, could tip the balance of the chances of success in our favor. In his study, Kerins proposes to use Game theory, in which there exists, he explains, a class of games, known as coordination games, that involve two players who have to cooperate to win, but who cannot communicate with each other.

When we do SETI searches, like whatever civilization is trying to find us, we are playing exactly that kind of game. So if they and we both want to make contact, we can both turn to game theory to develop the best strategy. Kerins has christened his idea “mutual detectability” so that the best places to look for signals would be those planets from which it was possible to determine if the Earth itself can be inhabited. If we have evidence of a potentially habitable planet -explains the researcher- and the civilization there has similar evidence about our planet, both sides should be equally motivated to undertake the search for each other because both would know that the evidence is mutual.

According to the new theory, therefore, it would be best to examine planets in transit (passing in front of their host stars) of terrestrial type (made of rock) and in the habitable zones of their suns, that is, at a distance correct so there can be liquid water on its surface. But not only that. The candidate planets must also be aligned with the Earth’s orbital plane.
In the words of Kerins, what if these planets are located in line with the plane of the Earth’s orbit? Well, they could see our planet transiting the Sun and they could access the same type of information about us that we have about them. The two planets would be mutually detectable.

The area from which it is possible to see our planet in transit through the Sun is known as the Earth Transit Zone. And according to the study, there should be thousands of potentially habitable planets in it. The question, however, remains whether we should limit ourselves to “listening” for a possible signal from these candidate worlds or whether, on the contrary, we should launch ourselves directly to send them our signals. The matter is not minor. Some scientists, including the late Stephen Hawking, warn of the potential dangers of sending signals to civilizations that we know nothing about and that could be technologically superior to us. Others, on the contrary, point out that if all civilizations have the same fear, then there will never be any sign that someone can detect. This is known as ‘The SETI paradox’, and in his, work Kerins shows a way to solve it.

In his article, in effect, the researcher explains that the possible civilizations of a planet located in the Transit Zone of the Earth can know which of the two worlds, theirs or ours, is more clearly visible from the other. Something that we too will know. According to Kerins, therefore, “it makes sense that the civilization with the clearest view of the other planet is more tempted to send a signal. The other party will know and should therefore actively watch and look for a sign.

Kerins believes that the vast majority of habitable planets in the Earth’s Transit Zone are in orbits around red dwarfs, stars of low mass, and less bright than the Sun, so they would have a clearer view from their position. of us than we have of them. Therefore, according to the theory of Mutual Detectability, specific SETI programs should concentrate on looking for signs of possible civilizations on potentially habitable planets around such stars.
“Soon,” says Kerins, “we should have available the first catalog of planets that may be inhabited by civilizations that already know something about our world. They may even know enough to be tempted to send a message. Those are the words we should focus on. If they know the Game theory, they will expect us to listen to them.